The present invention relates to an improved, light weight and durable door assembly incorporating a specialized door panel design. More specifically, the present invention relates to door assemblies for multi-bay beverage trucks, rear-door delivery trucks, or other applications requiring a vertical sliding access door.
Vertical sliding access doors are commonly used in multi-bay beverage trucks and rear-door delivery trucks. Traditionally it has been difficult to reduce the weight of these types of doors and maintain door strength, rigidity, durability, and the like. As a result it is necessary to either require operators to open and close very heavy doors or provide supplemental door lift assemblies. Each of these options is problematic for a variety of reasons. Accordingly, there is a need for a light weight, easily manufacturable, durable and reliable door assembly.
This need is met by the present invention wherein a door assembly is provided incorporating a specialized dual material door panel design. According to the present invention, as is described in detail herein, a door design is introduced that utilizes door panels including a metallic female member and a non-metallic or plastic male member. The resulting design is optimally rigid, durable, and lightweight By arranging the design such that the female member is a rigid metal (e.g., Aluminum) and the male member is a plastic material, a secure engagement between the male and female member may be maintained. The weight of a door assembly according to the present invention is minimized by forming a majority or substantial portion of each panel of the door assembly from a light weight plastic material (e.g., polyvinyl chloride (PVC)). Select portions of each panel are formed from a metallic material, e.g., aluminum, having more longitudinal rigidity than conventional Plastic to optimize the structural integrity of each panel and of the door assembly as a whole.
In accordance with one embodiment of the present invention, a door assembly comprising a plurality of interlocked door panels. Each of the door panels defines a length dimension, a height dimension, and a thickness dimension. Each of the door panels also defines a female portion, a male portion, and a panel body portion. The female portion and the male portion are defined near opposite extremes of the height dimension. The panel body portion mechanically couples the female portion to the male portion. The panel body portion is characterized by a lower density than the female portion. The female portion defines an inside diameter. The male portion defines an outside diameter. The inside diameter of the female portion is sized to accommodate the outside diameter of the male portion. Each of the door panels are interlocked to an adjacent one of the door panels via accommodation of a male portion of one of the panels within a female portion of another of the panels.
Preferably, the male portion and the panel body portion form an integral part of the door panel while the female portion defines a separate part of the door panel. Further, the volume of the panel body portion preferably exceeds the volume of the female portion. The panel body portion and the male portion may be formed from a plastic material, such as polyvinyl chloride (PVC), and the female portion may be formed from a metal, such as aluminum. The female portion and the male portion are preferably defined about respective parallel longitudinal axes extending along the length dimension of the door panel.
The panel body portion may define a channel therein and the female portion may define an extended base portion. The channel and the extended base portion preferably define dimensions that permit slidable insertion of the extended base portion into the channel portion. The slidable insertion of the extended base portion is characterized by frictional engagement of the extended base portion and the channel. One or more projections may be provided in the channel to enhance the frictional engagement of the extended base portion and the channel. The respective dimensions of the channel and the extended base portion may define an asymmetric key relationship.
The female portion, the male portion, and the panel body portion are configured such that accommodation of the male portion of one of the panels within the female portion of another of the panels defines a pivot axis about which the panels are free to pivot relative to one another. The female portion may define a leading edge and the male portion and the panel body portion may define a recess in which the leading edge is free to move as the panels pivot relative to one another.
In accordance with another embodiment of the present invention, a sliding access door assembly is provided comprising a plurality of interlocked door panels supported along parallel door tracks by a plurality of supporting wheel assemblies engaging individual ones of the interlocked door panels. Each of the door panels are interlocked to an adjacent one of the door panels via accommodation of a male portion of one of the panels within a female portion of another of the panels. Each of the male portions further defines an inside diameter sized to accommodate an axle of one of the supporting wheel assemblies. Each of the supporting wheel assemblies is secured to one of the interlocked door panels via insertion of an axle of one of the supporting wheel assemblies within a corresponding inside diameter of one of the male portions.
The door tracks typically define a travel path including a curved portion. Preferably, the female portion, the male portion, and the panel body portion are configured such that accommodation of the male portion of one of the panels within the female portion of another of the panels defines a pivot axis about which the panels are free to pivot relative to one another to an extent sufficient to permit transit of the door assembly through the curved portion of the travel path.
In accordance with yet another embodiment of the present invention, a transit vehicle is provided. The transit vehicle includes at least one storage bay enclosed by and accessed through a sliding access door assembly comprising a plurality of interlocked door panels supported along parallel door tracks by a plurality of supporting wheel assemblies engaging individual ones of the interlocked door panels. Each of the supporting wheel assemblies is secured to one of the interlocked door panels via insertion of an axle of one of the supporting wheel assemblies within a corresponding inside diameter of one of the male portions.
Accordingly, it is an object of the present invention to provide a door design that is optimally rigid, durable, and lightweight and a transit vehicle incorporating such a design. Other objects of the present invention will be apparent in light of the description of the invention embodied herein.